Microroentgenography of segments of the dorsal telencephalon following injection of the cortical arteries with a fine-grained injection material demonstrated arterial penetrating vessels into the cerebral cortex, small interconnecting vascular channels which were presumed to be either capillaries or arterio-venous connections or both, and larger pial surface veins and deep transcerebral veins. Further study using stereo microroentgenography as well as a study of segments of the dorsal telencephalon cleared or corroded following injection of the vasculature will be carried out. What is required is a method of visualizing the origin of the transcerebral veins in the cerebral cortex. This I hope to do with one of the above stated approaches.